According to our friends at Coors Field Forecast (a great follow on Twitter, by the way), a strong initial round of thunderstorms could move through the Denver metro area between (local time) 4-7 p.m. They say another round could impact the game right around its conclusion or the start of the fireworks display.
A check of the Denver NBC affiliate’s Web site shows (at the time of this writing) chances of rain this afternoon, including a 40 percent chance around 5 p.m. The chances then go down, but start to increase again around 8 p.